Polishing discs



May 17, 1960 P. JONES POLISHING nxscs 'Original Filed March 17, 1950attorney! ilnite States Patent 1 2,936,553 POLISHING DISCS Paul L.Jones, Columbus, Ohio, assiguor to General Motors Corporation, Detroit,Mich., a corporation of Delaware Original application March 17,

now Patent No. 2,698,783, dated January 4, 1955. Divided and thisapplication September '3, 1952, Serial No. 307,667

1 Claim. ((151-193) This is a division of application entitled Method ofMaking Polishing Discs, S.N. 150,126, filed in the name of Paul L. Joneson March 17, 1950, and now Patent No. 2,698,783, dated January 4, 1955.i

This. invention relates to bufiing or polishing discs for use in buffingor polishing various kinds of metallic and other surfaces.

Heretofore it has been customary to form polishing discs by spirallywinding a strip of textile fabric material upon a cylinder or arbor andthen gathering the middle portion of the cylindrically formed structureto bring the ends thereof together to provide an annular polishing toolor disc. Wire or other bands sometimes have been used for holding themiddle parts together to provide a relatively permanent size or diameterfor the inner peripheral parts of such discs. Such bands have been heldin place and the ends of the cylinderhave been held together by sewingthe fabric material around and closely adjacent the bands. Polishingdiscs formed in this manner naturally will have irregular innerperipheral securing edges for supporting the discs, such edgesconsisting of successively bunched or gathered sections'of irregularshapes and generally of many different but somewhat circularcross-sectional shapes. It has been the custom to force these discs upona polishing arbor with spacing devices therebetween and then to securethe discs in operative position by tightening a nut at one end of thearbor against an annular shoulder at the other. In order to be able toforce these discs upon the arbor it was necessary that the discs be madein such a way as to be only slightly smaller than the arbor. Otherwiseit would beimpossible to get the discs on the arbor by manual effort.When the spacing members thereafter were tightcued against the innerperipheral parts of 'the discs, the 5 acing members and the arbor wouldtend to compress 1 e fibrous structure of the inner peripheral parts ofthe discs to fit the arbor and the spacing members. However, thiscompressing of the fibrous structure of-the discs did not occur to themaximum extent when the discs were first put on the polishing jack ormachine. After the 1950, Serial N0. 150,126,

discs were run for a while, they would tend to get loose and then itwould be necessary again to tighten the securing nut of the arbor. Asthis tightening continued, the discs would tend to stretch at the innerperiphery thereof and get too large in diameter for the arbor.

Intermediate all these stretching and tightening operations the discswould not be as tight and well fitting as they should be so that theoperation thereof was uncertain, unsatisfactory, and unreliable. v

It is now proposed to preform polishing discs of this kind, in such away as to do' all of the compressing and compacting of the innerperipheral parts of the disc before they are first applied to apolishing arbor. Hence, when the discs are clamped upon an arbor foruse, the fibrous structure of the inner peripheral parts of-a disc willhave been previously compressed and compacted and preformed in suchmanner that they will fit the arbor and the clamping members of thearbor. Thereafter, when the tightening nut for the arbor is tightened tothe desired extent, the discs then will run until worn out and without'any further adjustment of the tightening nut.

An object of the invention, therefore, is to provide a polishing discthat will accurately fit the surface of an arbor and the annularclamping members for operating the polishing disc, so that discs can beput on an arbor without requiring excessive effort for forcing the discsonto the arbor and so that they may be clamped in such position as toremain permanently operative for polishing purposes.

Other and further objects of the invention will be apparent from thespecification and the drawing, and in which; I

Figure 1 is a perspective view of a rotary forming member having atextile fabric strip being spirally wound upon the cylindrical surfacethereof.

, Figure 2 is a perspective view of a cylindrical textile fabric workpiece as the work piece will appear after having been formed as isillustrated by Figure 1.

Figure 3 is a cross-sectional view illustrating the formation of anannular disc from the work piece illustrated by Figure 2. In Figure 3,the middle portion of the work piece is being contracted upon a formingtool for limiting the size of the inner peripheral part of the discbeing formed, and, the ends of the cylindrical work piece are beingbrought together to complete the formation of such disc.

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Figure 4 is a side elevational view of the disc-shape work piece afterthe same has been formed as is indicated byFigure 3 and after the twoends of the work piece have been stitched together around the innerperipheral parts thereof.

Figure 5 is a cross-sectional view of the disc-shape work pieceillustrated .by Figure 4 as the same would appear in the plane of line5--5 on Figure 4. V

Figure 6 is a vertical sectional view of an apparatus 4. In Figure 6,the fibrous structure of the inner peripheral parts of the disc-shapework piece illustrated by Figure 5 are rearranged and compressed andcompacted in such a way as to fit the supporting and clamping parts of apolishing tool with which such discs are to be employed as polishing orbufiing discs.

Figure 7 is a fragmentary cross-sectional view of a polishing jack,machine, mechanism, or fixture, illustrating the manner in which thepolishing discs formed by the process illustrated by the precedingfigures are secured in operative position upon the arbor of any suchdevice.

Referring particularly to Figure l, the numeral 10 indicates a formingcylinder on which an elongated strip of flexible textile fabric or othersimilar material indicated at 11 is adapted to be spirally wound toprovide a cylindrical work piece as indicated at 12.

The cylindrical work piece 12 is illustrated in Figure In Figure 3, thecylindrical workpiece 12 is indicated in dot-and-dash lines in the firststep of the process by which the work piece is converted into an annularwork .piece as is indicated at 13 in Figure 4.

positioned in any suitpiece 12 and then is progressively released togather by progressive stages the central portion of the work piece 12about the forming tool 14. The work piece 12 is illustrated at 17, inone of the intermediate stages by which the cylindrical work piece 12 ischanged into' an annular work piece indicated at 13. When the spring 16has contracted until the middle part of the work piece 12 engages theforming tool 14, the spring is removed and theends of the work piece arebrought together so as to provide an annular disc-shape Work piece asindicated at parts thereof as is indicated at 18.

A plurality of the work pieces 13 is then placed upon a forming toolindicated at 19.

The tool 19 comprises a hollow cylindrical part 21 having a closed andchamfered end indicated at 22, while the opposite end thereof is closedby a plate 23 which is larger in diameter than the diameter of thecylindrical part 21. The central portion of the plate 23 is recessed asindicated at 24 for receiving the end of the cylindrical part or member21. Beyond the cylindrical part 21, the plate 23 provides an outerannular part or shoulder indicated at 26, adapted to support upon theupper surface thereof a plurality of spaced annular forming membersindicated at 27L The forming members 27 have inner cylindrical surfacesadapted to accurately fit the exterior surface of the cylindrical part21 of the forming tool to provide good thermal conductivity between theparts. With such conductivity, the spacing members 27 will be heatedwhen the cylindrical part 21 is heated.

The opposite edges or the ends of the spacing members 27 are disposed inparallel relation and are surfaced and finished to provide smooth endsurfaces of annular shape.

The work pieces 13 are positioned between the adjacent surfaces of twoof the spacing members 27 to provide a series or stack of spacingmembers and work pieces about the outer surface of the cylindrical part21 and resting at one end upon the outer annular part 26 of the plate23.

The work pieces 13 are adapted to be positioned upon the cylindricalpart 21 by stretching the inner peripheral surfaces of the work piecesover the relieved end surfaces 28 of the cylindrical part 21. The innerperipheral parts of the work pieces are then adapted to be compressedbetween the spacing members 27 by applying to the stack of such workpieces and spacing members a press such as that indicated at 29. Thepress 29 compresses the work pieces 13 and the spacing member 27 againstthe annular part 26 of the plate 23 which in turn is supported by thebase plate of the press 29.

in order to be able to heat the cylindrical member 21 for evaporatingwater to form steam for thermally setting the fibrous structure of theinner peripheral parts of the work pieces 13, the plate 23 is providedwith an opening 31 at the central portion thereof and through which anysuitable liquid or gaseous heating fluid may be introduced to theinterior of the cylindrical member 21. The inner peripheral parts of thework pieces 13 are sprinkled or otherwise partially saturated with waterbefore being positioned upon the cylindrical member 21 and between thespacing members 27. When the cylindrical member 21 is heated by theintroduction of heating fluid to the interior thereof as previouslydescribed, the heat will be conducted to the cylindrical innerperipheral edges of the work pieces 13 by the exterior surface of themember 21. Such heat also will be conducted to the opposite annular endsof the inner peripheral parts of the work pieces 13 by conductivity ofheat from the member 21 to the spacing members 27. The heat so conductedby the cylindrical member 21 and the spacing members 27 will evaporatethe moisture so applied to the inner peripheral parts of the work pieces13 and will form steam which will thermally set the fibrous structure ofthe inner peripheral parts of the work pieces as the fibrous strucre ofsuch parts is compressed and compacted by the press 29 between thecylindrical member 21 and the spacing members 27. When this heatingprocess has been continued until all the water has been turned to steamby the conductivity of heat so described and the steam has beensuper-heated to some extent so that the setting of the fibrous structurewill be relatively permanent, the press is opened and the stack of workpieces 13 is removed from the cylinder 21.

When removed from the forming tool 19, the work pieces 13 will providefinished polishing discs such as are indicated by the numerals 32. Thepolishing discs 32 will have inner peripheral surfaces preformed to fitthe exterior surfaces of the arbor 33 of the polishing device with whichsuch discs are to be employed. Such polishing discs may be positioned onthe arbor 33 merely by piaeing the inner peripheral parts of the discsover the end of the arbor and pressing the discs firmly upon the arbor.The discs do not require excessive stretching in order to fit the arbor.

The inner peripheral parts of the discs 32 also fit the adjacentsurfaces of the securing nut 36, of the securing shoulder 37 and ofspacing members which may or may not be employed about the arbor 33 andbetween the polishing discs 32. When the securing nut 36 for the arbor33 is tightened on the threaded end of the arbor, the inner peripheralparts of the polishing discs 32 will be securely and permanently clampedbetween the members 36 and the securing shoulder 37 which is keyed orotherwise secured to the arbor 33. Thereafter the polishing fixture ordevice may be operated at will without having the polishing discs 32become loosened upon or otherwise improperly fitting the arbor 33.

I claim:

An annular polishing disc for use with a rotatable arbor having anannular securing shoulder at the inner end and an annular securing nutat the outer end, said nut being removable from said arbor for securingsaid disc on said arbor and against said shoulder, said polishing dischaving an outer edge and a hub and substantially parallel sides andcomprising a fibrous material forming a flexible fabric strip havingparallel edges and a middle, said middle and said parallel edgesincluding substantially equal lengths of said strip, said strip edgesbeing at said outer edge of said disc and said strip middle being at thesaid hub of said disc and with said sides of said disc being parts ofsaid s'trip between said strip edges and said strip middle, said stripat said hub before being secured on said arbor and throughout theoperation of said disc on said arbor including an inner relativelysmooth cylindrical surface and at the ends of said cylindrical surfaceincluding parallel and relatively smooth end surfaces, said surfacesforming substantially right angular corners between said inner and saidend surfaces of said hub, the fibers of said fibrous material with nsaid hub being compactly disposed and mechanically interlocked andpermanently set and providing a rigidly an continuously operable annularbody bounded by said surfaces and said corners for operatively androtatably supporting said disc on said arbor, said smooth cylindricalsurface and said corners being of a form to receive and tightly toengage and slidably to fit said arbor, said end surfaces being of a formuniformly to engage the adjacent sides of said shoulder and said nut andfrom the inner to the outer extremities of the adjacent sides of saidshoulder and said nut, said compactly disposed and mechanicallyinterlocked and permanently set fibers maintaining said bodysubstantially in uniformly engaged relation with said arbor and saidshoulder and said nut and throughout the operation of said disc on saidarbor and until said disc is rendered inoperative by wearing out saidouter edge of said disc.

References Cited in the file of this patent UNITED STATES PATENTS HallOct. 5, 1948 Webster Feb. 5, 1895

